Compression release arrangement for internal combustion engines



June 14, 1966 D. E. WEGLAGE ETAL COMPRESSION RELEASE ARRANGEMENT FOR INTERNAL COMBUSTION ENGINES Filed April 2, 1965 6 Sheets-Sheet l I V IIIIIIIl lilllil Will/[A711 INVENTORS DAVID E. WEGLAGE BY ALBERT A. WEGLAGE June 14, 1966 D. E. WEGLAGE ETAL COMPRESSION RELEASE ARRANGEMENT FOR INTERNAL COMBUSTION ENGINES Filed April 2, 1963 6 Sheets-Sheet 2 II I DAVID E. WEGLAGE y A LB ERT A. WEGLAGE June 14, 1966 D. E. WEGLAGE ETAL 3,255,744

COMPRESSION RELEASE ARRANGEMENT FOR INTERNAL COMBUSTION ENGINES 6 Sheets-Sheet 5 Filed April 2, 1963 VA LV E FOR ill 2 DIA. PISTON INVENTORS DAVID E. WEGLAGE BY ALBERT A. WEGLAGE June 14, 1966 D. E. WEGLAGE ETAL 3,255,744

COMPRESSION RELEASE ARRANGEMENT FOR INTERNAL COMBUSTION ENGINES Filed April 2, 1965 6 Sheets-Sheet 4 INVENTORS DAVID E. WEGLAGE ALBERT A.WEGLAGE June 14, 1966 D. E. WEGLAGE ETAL 3,255,744

COMPRESSION RELEASE ARRANGEMENT FOR INTERNAL COMBUSTION ENGINES Filed April 2, 1963 6 Sheets-Sheet 5 l7 oAvlb z zY x az fAse BY ALBERTA. WEGLAGE J1me 1956 D. E. WEGLAGE ETAL 3,255,744

COMPRESSION RELEASE ARRANGEMENT FOR INTERNAL COMBUSTION ENGINES Filed April 2, 1963 6 Sheets-Sheet 6 T 1 Lg E1 I INVENTORS l DAVID E. WEGLAGE BY ALBERTA. WEGLAGE United States Patent COMPRESSION RELEASE ARRANGEMENT FOR INTERNAL COMBUSTION ENGINES David E. Weglage and Albert A. Weglage, Dayton, Ohio, assignors of one-third to Walter Becker, Dayton, Ohio Filed Apr. 2, 1963, Ser. No. 269,926 9 Claims. (Cl. 123-482) The present invention relates to internal combustion engines, and, more particularly concerns the manual starting of internal combustion engines.

The manual starting of internal combustion engines, particularly those used in connection with garden and agricultural implements such as lawn mowers, has been quite some problem, and various attempts have been made to facilitate the manual starting of such engines.

Thus, it has been suggested to bore a small hole of approximately .013 in diameter through the cylinder head to somewhat reduce the compression during the starting period of the engine. However, such an arrangement, while slightly easing the abovementioned problem, has not solved nor can solve said problem. This is due primarily to the fact that the bore is far too small in diameter in order effectively to release the compression during the starting period. On the other hand, since the bore remains open permanently and thus causes a permanent compression loss, the diameter of said bore cannot be increased to an extent where it would materially ease the starting of the engine, since the permanent compression loss would be unbearable and prohibitive.

According to another effort to ease the manual starting of internal combustion engines, one of the cams on the cam shaft which normally control the inlet and outlet valves has its profile reshaped so as to delay the final closure of the respective valve during the compression stroke of the engine. While this arrangement has eased the starting of a correspondingly,designed engine, it, too, has the drawback that it is operative throughout the entire running period of the engine and thus actually interferes with the otherwise possible top performance of the engine design. Furthermore, also this arrangement does not and cannot, during the manual starting operation, release the compression to the desired extent because the modified cam controlled valve closes and must close before the end of the compression stroke of the engine.

It is, therefore, an object of the present invention to provide compression release means for facilitating the manual starting of an internal combustion engine, which will overcome the above-mentioned drawbacks.

It is another object of this invention to provide compression release means for an internal combustion engine, which will be operative during the starting of the engine only and will not affect the normal operation of the engine.

It is another object of this invention to provide compression release means for internal combustion engines, which will be independent of the cam shaft of the engine.

It is still another object of this invention to provide compression release means for internal combustion engines, which will become effective automatically with the customary shifting of the choke lever to choke position for starting, and will become automatically ineffective with the customary returning of the choke lever to its position for normal operation of the engine.

It is still a further object of this invention to provide compression release means as set forth in the preceding paragraphs, which will not require any valves in addition to the normal valves in the engine.

Still another object of this invention consists in booking up the compression release means according to the invention as set forth in the preceding paragraphs with the choke lever in such a way that activation of one and the same Bowden wire customarily connected to the choke 3,255,744 Patented June 14, 1966 lever will also operate the compression release means according to the invention.

These and other objects and advantages of the invention will appear more clearly from the following specification in connection with the accompanying drawings, in which:

FIGURE 1 is a partial section through a portion of a cylinder block and the cam shaft containing housing of a four-stroke cycle internal combustion engine, the inlet and outlet valves being shown in their closed positions;

FIGURE 2, is a partial section similar to that of FIG- URE 1 but with the outlet valve partially opened by the compression release mechanism according to the present invention;

FIGURE 3 is a partial section similar to that of FIG- URES 1 and 2 but with the inlet valve fully opened by the control cam in conformity with the normal operation of the engine;

FIGURE 4 is a section along the line IV-IV of FIGURE 1 showing the compression release member according to the present invention in its inoperative or neutral position;

FIGURE 5 is a view of FIGURE 4 as seen in the direction of the arrow A;

FIGURE 6 is a section similar to that of FIGURE 4 but showing the compression release member of the invention in its effective position;

FIGURE 7 is a view of FIGURE 6 as seen in the direction of the arrow B;

FIGURE 8 shows by way of example the dimensions of an actual valve and of the effective valve gap produced by the compression release mechanism according to the present invention with such valve, for obtaining highly satisfactory compression release;

FIGURE 9 shows a lawn mower equipped with a compression release according to the invention and illustrates the means at the push handle for actuating the compression release;

FIGURE 10 illustrates a coupling between the choke lever and the compression release actuating lever according to the invention;

FIGURE 10a is a view along the line XaXa of FIG- URE 10;

FIGURE 11 is a slight modification of the compression release member according to the invention as shown in FIGURES 4'to 7, and differs therefrom in that, while according to FIGURES 4 to 7, the pressure release member is a bolt-like member threadedly engaging a threaded bore in the housing containing the cam shaft, according to FIGURE 9, the compression release member is a nut threadedly engaging a threaded bolt which is fixedly connected to the housing containing the cam shaft;

FIGURES 12 and 13 illustrate in view in ineffective and effective position respectively a modified compression release member according to the invention with cam surface means;

FIGURE 14 represents partially in section a further and preferred embodiment of the compression release mechanism according to the invention in its ineffective position;

FIGURES 14a and 14b on a greatly enlarged scale show a detail of the cam race of FIGURE 14;

FIGURE 15 shows the compression release mechanism of FIGURE 16 in its effective position;

FIGURE 16 is a section taken along the line XVIXVI of FIGURE 17 and illustrates in particular the actuating means for the compression release mechanism of FIG- URES 16 and 17;

FIGURE 17 illustrates a top view of FIGURE 16 and shows the choke and throttle control lever as means for controlling the actuating means for the compression release mechanism according to the invention, said control lever occupying a position in which the compression release mechanism is in its ineffective position, as shown in FIGURE 14;

FIGURE 18 is a section similar to that of FIGURE 16 but with the compression release mechanism in its effective position as shown in FIGURE 15, the section of FIG- URE 18 being taken along the line XVIIIXVIII of FIGURE 19;

FIGURE 19 is a view similar to that of FIGURE 17 but with the choke control lever in its full choking position in which the compression release mechanism is in its effective position as shown in FIGURE 15;

FIGURE 20 is a section through the upper portion of a cylinder and the adjacent cylinder head portion with a further modified compression release mechanism according to the invention, in which said release mechanism includes a valve;

FIGURE 21 is a section similar to that of FIGURE 20 but with still a further modified compression release valve.

General arrangement According to the broadest aspects of this invention, the compression chamber of the internal combustion engine, preferably a wall of the cylinder block, is provided with a passage adapted selectively to be closed or opened by a valve which is operable from the outside of the engine, preferably from a point remote therefrom, and completely independently of the piston stroke. Advantageously, when the engine is mounted on a horticultural or agricultural implement having a push handle, the said valve is operatively connected to a lever on said push handle.

The compression release according to the present invention may be realized in a particularly simple manner with a four-stroke cycle internal combustion engine having an intake valve, an exhaust valve, push rod means therefor, and a cam shaft for actuating said push rod means. More specifically, with an engine of this type, one of said valves, preferably the exhaust valve, has, according to the present invention been provided with valve stem lifting means operable selectively and independently of said cam shaft for lifting the valve stem and a valve pertaining thereto into a desired opening position to establish compression release for any desired length of time. The arrangement is such that the actuation of said valve stem lifting means does not impede or interfere with the actuation of said push rod means by said cam shaft. In this connection, it is particularly advantageous and convenient to use the normally provided choke or throttle lever both as such lever and as control lever for said valve stem lifting means.

Structural arrangement Referring now to the drawings in detail and FIGS. 1 to 3 thereof in particular, the arrangement shown therein comprises a cylinder block 1 with a cylinder 1a (a portion thereof only :being shown). Mounted on cylinder block 1 in customary manner is a cylinder head 1b. Cylinder block 1 comprises a spring chamber 2 which has connected thereto a housing 3. J ournalled in said housing 3 is a cam shaft 4 which is drivingly connected to the crankshaft (not shown) of the engine in a manner customary with four-stroke-cycle internal combustion engines and disclosed e.g. in US. Patent 2,999,491. In customary manner cam shaft 4 is provided with a first earn 5 and a second cam 6. Cam 5 engages a push rod 7 which in turn is adapted to engage the stem 8 of the exhaust valve 9 of the engine controlling the connection of the cylinder with an exhaust port (not shown) through a passage 10. In FIG. 1, valve 9 is shown in its closed position in which it is seated on valve seat 10 by means of a spring 11. One end of spring 11 rests against the spring chamber wall 12, whereas the other end of spring 11 rests on a spring keeper 13 holding spring 11 under pre-load and being held in its position on one hand by a pin 14 extending through valve stem 13, and on the other hand by said spring 11. As will be evident from FIG. 1, valve stem 8 extends somewhat beyond the spring keeper 13 and pin 14 in the direction toward the push rod 7.

Housing 3 is provided with a threaded bore 3a threadedly engaged by threaded section 15 of a member 15 which may also be termed pressure release button, for a reason which will presently appear. Pressure release button 15 has a :bore 16 into which slidably extend push rod 7 and valve stem 8. The peripheral portion of pressure release button 15 is provided with an ear 17 (FIGS. 5 to 7) engaged by a hook-shaped end of a Bowden wire 18 extending into the spring chamber 2 through a tube 19 connected to the wall of the spring chamber 2 in any convenient manner.

By actuation of Bowden wire 18, pressure release button 15 is adapted to be turned about the longitudinal axis of valve stem 8 from its ineffective position (shown in FIGS. 1, 4 and 5), in which the button surface 15a engages the surface 3b of housing 3 into its effective position (shown in FIGS. 2, 6 and 7), in which the button surface 15a is spaced from the housing surface 3b. The button surface 15b is provided with a shallow circular recess 20 the bottom of which is slightly spaced from pin 14 when button 15 occupies its ineffective position, and engages pin 14 when button 15 moves out of its ineffective position into its effective position. .Preferably, the diameter of resess 20 is only slightly in excess of the length of pin 14. When compression release button 15 thus engages pin 14, it lifts valve 9 off its seat 10' to an extent corresponding to the desired compression release. The spacing s (FIG. 8) by which the valve 9 in this way is lifted off its seat 9 may vary within a wide range, depending on the diameter of the valve, and may, for

.instance, be .009" with a valve having an outer diameter of .845, a taper of 45 and a thickness of .133", all as shown in FIG. 8. However, successful tests have also been conducted with a spacing within the range of from .005 to .020.

The engine portion illustrated in FIGS. 1 to 3 is, in customary manner, also provided with an inlet valve 21 spring-biased into closing position and operable by cam 6 through the intervention of a push rod 22. Valve 21 controls the comunication of the cylinder with a fuel inlet port (not shown) through a passage 1d.

Operation 0 the arrangement of FIG. 1 to 7 It may be assumed that an internal combustion engine equipped with the compression release mechanism of FIGS. 1 to 7 is to be started. To this end the Bowden wire 18 is actuated so as to effect a turning movement of the compression release button 15 and to turn the same from its ineffective position, shown in FIGS. 1, 4 and 5, into its effective position, shown in FIGS. 2, 3, 6 and 7. As a result thereof, compression release button 15 enages pin 14 and lifts the same against the thrust of spring 1 so as to lift valve 9 off its seat 10' to a desired extent, for instance, by a distance of 0.009, depending on the axial movement of the button 15 as a result of its turning movement. Inasmuch as the actuation and position of compression release button 15 is totally independent of and does not interfere with the operation of the cam shaft and push rods actuated by said cam shaft, it will be appreciated that, when the flywheel and crankshaft of the engine (not shown) are rotated, cam shaft 4 drivingly connected thereto in customary manner will act upon the push rods 7 and 22 pertaining to valves 9 and 21 respectively. Therefore, inlet valve 21 will open and close in its normal way and conventional manner, and exhaust valve 9 will likewise be opened by cam 5 in conventional manner (see FIG. 3). However, exhaust valve 9 cannot close beyond the distance it has been lifted off its seat 10 by button 15, which means that valve 9 will remain open to a certain desired extent throughout the entire engine cycles as long as button 15 remains in its its ineffective position of FIGS. 1 and 5. When button 15 has thus been returned to its ineffective position, it disengages pin 14, and a valve stem 8 is now fully and only under the influence of its spring 11 and push rod 7 so that cam 5 operaes the exhaust valve 9 in normal and conventional manner. This means that exhaust valve 9 will be able fully to close in conformity with the conventional operation of conventional internal combustion engines and conventional design of the cam on the cam shaft, so that full compression will be assured during the normal operation of the engine, and no compression will be lost at any time during the normal engine operation.

The actuation of the Bowden wire 18 may be effected from any convenient point of the implement equipped with the engine having a compression release mechanism according to the present invention. Thus, assuming that the engine E of the lawn shown in FIG. 9 has a compression release according to the present invention, the Bowden wire 18 may conveniently be passed along the push handle 23 and hooked up to a compression release control lever 24 on said handle. For the sake of convenience, this lever 24 may be located next to the customarily provided throttle and choke lever 25 for the engine E. For additional convenience, compression release lever 24 may be linked up with the throttle and control lever 24 in the manner shown in FIGS. and 10a. As will be seen from these figures, throttle and choke lever 25 has, by means of a pivot 26 linked thereto a link 27 provided with a slot 27a which is slidably engaged by a pin 24a extending through compression release lever 24. Connected to link 27 in any convenient manner, for instance by welding, is a spring supporting arm 28 movably extending through an abutment 29 which is fixedly connected to handle 23 by means of an arm 23a and a bracket 23b. Engaged by abutment 29 is one end of a compression spring 30 the other end of which has connected thereto a washer 31. FIG. 10 shows compression release lever 24 in its ineffective position and throttle and choke lever 25 in its Off-On position. In this position of levers 24 and 25 in which spring 30 is in its relaxed position, washer 31 is either just engaging lever 24 or slidably spaced therefrom, While pin 24a is spaced from the right-hand end (with regard to the drawing) of the slot 27a.

If it is now desired to start the engine, throttle or choke lever 25 is shifted in the direction of the arrow Z to starting position. While this is being effected, pin 24a is eventually engaged by the right-hand end wall of slot 27a at which instant lever 24 will be shifted in counterclockwise direction together with lever 25, while spring 311 is being compressed. In this way, lever 24 will, through the intervention of Bowden wire 18, shift the compression release button into its effective or compression release position. When the engine has been started, lever 25 is moved in clockwise direction into the position for normal operation, as is generally customary, whereupon spring 30 will return compression release lever 24 into its ineffective position shown in FIG. 10, and as a result thereof, compression release button 15 will be returned to its ineffective position. The engine will then run without any compression loss. As will be evident from FIG. 10, it is, of course, also possible to actuate the compression release lever 24 without actuating the combined throttle and choke lever 25.

Modifications of compression release members (FIGS. 11 to 15) While the compression release member or button 15 of FIGS. 1 to 7 consists substantially of an annular member having a threaded extension 1517 in threaded engagement with a threaded bore 3a of housing 3, the modification of FIG. 11 shows substantially the opposite arrangement. More specifically, housing 3 has cast thereinto and anchored therein a threaded stud 32 which is threadedly engaged by a compression release nut or button 33a that is operable by the Bowden wire 18 in the same manner as described in connection with FIGS. 1 to 8. All other parts of the modification of FIG. 11 correspond to those of FIGS. 1 to 8, and accordingly, have been designated with the same reference numerals as in FIGS. 1 to 8.

According to the modification of FIGS. 12 and 13, the stud 32 of FIG. 11 has been replaced by an element 33 connected in any convenient manner, for instance by casting, to housing 3 and provided with a cam surface Cam surface 33a cooperates with a cam surface 34a which corresponds to the cam surface 33a and pertains to a compression release button 34. All other parts of FIGS. 12 and 13 correspond to those of FIGS. 1- to 8 and have, therefore, been designated with the same reference numerals. It will be appreciated that, when compression release button 34 is turned from its ineffective position of FIG. 12 into its effective position of FIG. 13, it rides on cam surface 33a and while moving toward the left (with regard to the drawing) lifts valve stem 8 and thereby lifts valve 9 off its seat 10 precisely as described in connection'with FIGS. 1 to 3.

The modification of FIGS. 14 and 15 is similar to that of FIGS. 12 and 13 inasmuch as it likewise employs cam surface means for imparting an'axial movement upon the compression release member. More specifically, housing 3 has connected thereto a plate 35 with a plurality of inclined cam surface depressions 36, for instance three evenly spaced cam surface depressions. The said plate 35 forms a race with one ball 37 each in each of said depressions 36. Cooperating with race plate 35 and balls 37 in depressions 36 is a race plate 38 likewise provided with inclined depressions 39 which, in FIG. 14, are located directly opposite depressions 36, as is particularly clearly shown on an enlarged scale in FIG. 14a. From FIGS. 14, 14a and 14b it will also be seen that the inclinations of both depressions 36 and 39 are directed in the same direction, viz. opposite to the direction of the arrow L.

Race plate 38 has near its marginal portion connected thereto a pin 40 which may be connected to Bowden wire 18 in the manner that Bowden wire 18 is connected to button 15 according to FIGS. 1 to 7.

Interposed between pin 14 and race plate 38 is the compression release button 41 into which extend the adjacent ends of the push-rod 7 and valve stem 8 in the same manner as described in connection with FIGS. 1 to 7. Butt-on 41 also has a shallow circular recess 20 for cooperation with pin 14, likewise as described in connection with FIGS. 1 to 7. The arrangement otherwise corresponds to that of FIGS. 1 to 7. When button 41 is in its ineffective position, it just fits in between race plate 38 and pin 14 without exerting a pressure on the latter.

Modified actuating mechanism for compression release button (FIGS. 14 to 19) in a loose slip-fit through andis guided by a bore 43 in spring chamber wall portion 30 (FIGS. 16, 18). Due

to the length of rod 42 and a light spring therein, the flat end 42a can easily follow the small axial displacement of race plate 38, which axial displacement amounts to a few thousandths of an inch corresponding to the compression release opening, for instance to .009". The other end of the control rod 42 has a knob or head 42b which is normally engaged by the rounded end of an adjustable screw 44 threadedly supported by a yoke 45 connected to spring chamber wall portion 30. Interposed between wall portion 3c and knob 42b is a spring 46 continuously urging knob 42b in a direction toward screw 44. It will be appreciated that, when button 42b and thereby rod 42 is pressed downwardly with regard to FIG. 16, button 41 will turn, and valve 9 will be lifted off its seat 10 as described in connection with FIGS. 14 and 15.

According to a particularly simple arrangement of the present invention, the actuation of control rod 42 with knob 42b is effected by the combined throttle-choke lever customarily provided with gasoline engines.

More specifically with regard to FIGS. 17 and 19, the throttle-choke lever shown therein has been designated with the reference numeral 47. According to FIG. 17, lever 47 occupies a position in which the butterfly 48 of the choke 49 is in fully opened position, whereas in FIG. 19, lever 47 occupies a position in which butterfly 48 is in its closed position, which means that lever 47 occupies its choke position. In conformity with a wellknown construction, lever 47 is pivotally mounted on a pin 50 and has an car 51 to which is connected a Bowden wire 18a for actuating lever 47 in either direction. Furthermore, in conformity with a standard construction of such throttle-choke lever, the butterfly 48 is connected to a pivot pin 48a and by means of a spring (not shown) is continuously urged into fully open position, while a segment shaped plate 52 is fixedly connected to said pivot pin and butterfly and has a slot 42a. Slot 52a is engaged by one end portion of a wire 53 the other end portion of which engages a slot 47a of lever 47. From FIGS. 17 and 18 it will be seen that, when lever 47 is being moved by Bowden wire 18a from its FIG. 17 position, in which butterfly 48 is in fully open position, toward FIG. 19 position, lever 47 will by means of wire 53 and segment 52 move butterfly 48 into its choke position.

According to the present invention, lever 47 is provided with a blade portion 54 (see also upper portion of FIGS. 16, 18). When lever 47 is moved from its FIG. 17 position to its FIG. 19 position, blade 54 slips between the rounded end of screw 44 and knob 4211 (see FIG. 18) thereby pressing rod 42 downwardly and cansing race plate 38 to turn from the FIGS. 14, 16 position into the FIGS. 15, 18 position. This, in turn, results in an axial movement of compression release button 41 as outlined in connection with the description of FIGS. 14 and so that valve 9 will be lifted off its seat 10. This situation remains until lever 47 is turned to such an extent that blade 54 slips out from between screw 44 and knob 42b, whereupon the spring 46 automatically lifts rod 42 and thus causes race plate 38 to return to its FIG. 14 position whereupon spring 11 is free to perform its normal function in the course of which it closes valve 9 during the compression stroke.

It will be appreciated from the above and from the drawings that return of lever 47 from choke position into any of its positions in which blade 54 has been Withdrawn from between knob 42b and pin 44, automatically makes the compression release ineffective, and the engine operates in the same manner as it would if the compression release of the present invention were not at all present. Looking at it from the opposite direction, it will be appreciated that in order to be able to take advantage of the compression release according to the present invention, it is not necessary that the lever 47 occupies its choke position. The compression release system becomes effective already at a point prior to lever 47 reaching its FIG. 19 position on its way from its FIG. 17 to its FIG. 19 position. This is of importance for starting with lever 47 in a non-choke position.

While the present invention has been described in connection with the exhaust valve 9, it is, of course, to be seat 67 for cooperation with a valve 68.

8. understood that, while this is preferable, it is by no means limited thereto and that the compression release system according to the invention is also operable when applied to the intake valve 21.

Modification of FIGS. 20, 21

Referring now to the embodiment of FIG. 20, the arrangement shown therein illustrates a compression release system which is applicable to both, internal combustion engines with cam shaft operated valves as well as to internal combustion engines which, as for instance, twostroke cycle engines, do not have cam shaft operated valves. More specifically, FIG. 20 shows a portion of a compression chamber 55 confined by a cylinder block 56 and a cylinder head 57. Cylinder head 57 has a threaded bore 58 therein which is threadedly engaged by a compression release button 59 somewhat similar to button 15 of FIG. 1. In contradistinction to button 15, however, button 59 has connected thereto a stem 60 with valve 61 for cooperation with the valve seat 62. In addition thereto button 59 has one or more compression release bores 63 the total free cross-section of which should equal at least the free cross-section of the gap between valve 61 and valve seat 62 when valve 61 is lifted off its seat by button 59 for the compression release.

The actuation of compression release button 59 is precisely the same as described in connection with the preceding embodiments. In other words, the compression release button 59 is connected to member 64 which may form the free end of of Bowden wire or the end of a control rod 42 described in connection with FIGS. 14 to 18. Thus, when button 59 is connected, for instance with rod 42, it will become effective and ineffective automatically with the shifting of throttle-choke lever 47 into the respective positions thereof, as described in connection with FIGS. 17 and 19, the compression being released through bore or bores 63.

Finally, the modification of FIG. 21 shows a compression release arrangement which is somewhat modified over that of FIG. 20. According to FIG. 21, the cylinder head 57a has cast thereinto an insert 65 with a recess 66 the lower edge portion of which forms a valve Connected to valve 68 is a valve stem 69 extending through a bore 70 in insert 65 and having its upper end provided with a thread 71. The threaded stern portion 71 is threadedly engaged by a compression release button 72. Button 72 has an annular flanged portion 72a carrying adjustable pins 73 which engage a corresponding groove 74 for preventing axial movement of button 72 while permitting rotative movement thereof. To prevent rotative movement of valve stem 69 while permitting axial movement thereof, valve stem 69 has an axially extending slot 71a through which extends a pin 75 mounted in insert 65. Button 72 is, similar to button 59, provided with a member 64 which may form the free end of a Bowden wire or of a control rod 42a similar to the control rod 42 of FIGS. 16 and 18. Insert 65 is additionally provided with one or more bores 76 having the same function as bore 63 of FIG. 20.

It will thus be obvious from the above that, when compression release button 72 is rotated for compression release purposes, valve stem 69 will be displaced axially, and valve 68 will be lifted off the seat 67 to an extent required for the desired compression release similar to valve 61 of FIG. 20, the compression escaping through bore or bores 76. Also in this instance, when button 72 is connected to rod 42a, it is made effective and ineffective automatically in the same manner as button 59 of FIG. 20.

It will also be appreciated from the above that the arrangement according to the invention, as it is illustrated in FIGS. 16 and 18, also makes it possible to take care of engine wear as far as lost compression is concerned.

Thus, it is merely necessary to adjust the adjusting screw 44 in an upward direction with regard to the drawing.

It is, of course, to be understood that the present invention is, by no means, limited to the particular con structions shown in the drawings, but also comprises any modifications within the scope of the appended claims.

What we claim is:

l. In a four-stroke cycle internal combustion engine having a cylinder block with a cylinder and with fuel intake passage means leading to said cylinder and with exhaust gas outlet passage means leading from said cylinder to the atmosphere: inlet valve means for opening and closing said fuel intake passage means with regard to said cylinder, reciprocable outlet valve means for opening and closing said exhaust gas outlet passage means with regard to said cylinder, each of said inlet and outlet valve means having a valve stem and push rod means operable to act upon the respective valve stem pertaining thereto for opening th respective valve means, rotatable cam shaft means with cams for actuating said push rod means, a plurality of spring means respectively operatively connectcd to said inlet and outlet valve means and continuously urging the same to close the passage means controlled thereby with regard to said cylinder, and a mechanically turnable annular compression release member substantially coaxially arranged with regard to the stem of one of said valve means and humble relative thereto while surrounding the push rod means pertaining to said last mentioned stem, said compression release member being operable in response to a turning movement thereof in one direction to carry out a movement in axial direction of the stem of said one valve means and in the opening direction thereof to actuate the valv stem of said one valve means so as the latter opens the passage means controlled thereby With regard to said cylinder, said compression release member being operable independently of each of said push rod means so as selectively to be held stationary relative thereto.

2. In a four-stroke cycle internal combustion engine having a cylinder block with a cylinder and with fuel intake passage means leading tosaid cylinder and with exhaust gas outlet passage means leading from said cylinder to the atmosphere: inlet valve means for opening and closing said fuel intake passage means with regard to said cylinder, reciprocable outlet valve means for opening and closing said exhaust gas outlet passage means with regard to said cylinder, each of said inlet and outlet valve means including stem means, rotatable cam shaft means with cams for actuating said cam means to cause said inlet and outlet valve means to open in a predetermined sequence in the course of the rotation of said cam shaft means, a plurality of spring means respectively operatively connected to said inlet and outlet valve means and continuously urging the same to close the passage means controlled thereby with regard to said cylinder, said stem means comprising holding means for holding the spring means pertaining thereto under a pre-load, compression release means independent of said shaft means and embracing the stern means of one of said valve means While being rotatable relative. thereto, and mechanical means operatively connected to said compression release means and operable in response to a certain rotation thereof in one direction to move the holding means pertaining to said one valve means in opening direction of the latter to thereby move said one valve means against the thrust of the spring means pertaining thereto into position for opening the passage means controlled thereby with regard to said cylinder.

3. In a four-stroke cycle internal combustion engine having a cylinder 'block with a cylinder and with fuel intake passage means leading to said cylinder and with exhaust gas outlet passage means leading from said cylinder to the atmosphere: inlet valve means for opening and closing said fuel intake passage means with regard to said cylinder, reciprocable outlet valve means for opening and closing said exhaust gas outlet passage means with regard to said cylinder, each of said inlet and outlet valve means having valve stem means, rotatable cam shaft means with cams for actuating said valve stem means, a plurality of spring means respectively operatively connected to said inlet and outlet valve means and continuously urging the same to close the passage means controlled thereby with regard to said cylinder, and annular compression release means surrounding the valve stem means of one of said valve means and movabl independently of said cam shaft means in axial direction of said last mentioned valve stem means and relative thereto for moving said one valve means against the thrust of said spring means into position for opening the passage means controlled thereby With regard to said cylinder, said annular compression release means being formed by a threaded first member and a threaded second member threadedly engaging each other in a nut-bolt manner.

4. In a four-stroke cycle internal combustion engine having a cylinder block with a cylinder and with fuel intake passage means leading to said cylinder and with exhaust gas outlet passage means leading from said cylinder to the atmosphere, said combustion engine also comprising throttle-choke lever means for controlling the throttle and the choke: inlet valve means for opening and closing said fuel intake passage means with regard to said cylinder, reciprocable outlet valve means for opening and closing said exhaust gas outlet passage means with regard to said cylinder, each of said inlet and outlet valve means having valve stem means, rotatable cam shaft means with cams for actuating said valve stem means, a plurality of spring means respectively operatively connected to said inlet and outlet valve means and continuously urging the same to close the passage means controlled thereby with regard to said cylinder, annular compression release means surrounding the valve stem means of one of said valve means and movable independently of said cam shaft means in axial direction of said last mentioned valve stem means from an ineffective position in which it does not affect said one valve means into an effective position for causing said valve stem means pertaining thereto to move said one valve means into position for opening the passage means controlled thereby with regard to said cylinder, actuating means, means associated with said actuating means for continuously urging the latter to hold said compression release means into its ineffective position, and means operatively connected to said throttle-choke lever means and operable in response to the movement thereof into a certain position to actuate said actuating mean-s to move said compression release valve means into its effective position.

5. In a four-stroke cycle internal combustion engine having a cylinder block with a cylinder and with fuel intake passage means leading to said cylinder and with exhaust gas outlet passage means leading from said cylinder to the atmosphere, said combustion engine also having throttle-choke lever means for controlling the throttle and choke of said engine: inlet valve means for opening and closing said fuel intake passage means with regard to said cylinder, reciprocable outlet valve means for opening and closing said exhaust gas outlet passage means with regard to said cylinder, each of said inlet and outlet valve means having valve stem means, rotatable cam shaft means with cams for actuating said valve stem means, a plurality of spring means respectively operatively connected to said inlet and outlet valve means and continuously urging the same to close th passage means controlled thereby with regard to said cylinder, compression release means independent of said cam shaft means and substantially coaxially arranged with regard to the valve stem means of one of said valv means and movable from an ineffective position in which it does not affect said one valve means into an elfective position in which it effects movement of said one valve means into l1 position for opening the passage means controlled thereby with regard to said cylinder, and means operatively connecting said compression release means with said throttlechoke lever for simultaneous and automatic operation of said compression release means with said throttle-choke lever means.

6. In a four-stroke cycle internal combustion engine having a cylinder block with a cylinder and with fuel intake passage means leading to said cylinder and with exhaust gas outlet passage means leading from said cylinder to the atmosphere, said combustion engine also having throttle-choke lever means for controlling the throttle and choke of said engine: inlet valve means for opening and closing said fuel intake passage means with regard to said cylinder, reciprocable outlet valve means for opening and closing said exhaust gas outlet passage means with regard to said cylinder, each of said inlet and outlet valve means having stern means operatively connected thereto, rotatable cam shaft means for actuating said stem means and thereby the valve means operatively connected thereto, spring means respectively associated with said valve means for continuously urging the same into position for closing the passage means controlled thereby with regard to said cylinder, compression release means independent of said cam shaft means and associated with one of said valve means, said compression release means being movable selectively from an ineffective position in which it does not affect the said one valve means to an effective position for causing said one valve means to occupy a position for establishing communication between the passage means controlled thereby and said cylinder, and means openatively connecting said throttle-choke lever means with said compression release means and operable in response to a certain minimum movement of said throttle-choke lever means in a certain direction to move said compression release means into effective position.

7. An arrangement according to claim 6, in which said means operatively connecting said throttle-choke lever means with said compression release means includes spring-biased connecting rod means, and in which said throttle-choke lever means has an arm operable to engage said connecting rod means.

8. An arrangement according to claim 6, which includes actuating means for actuating said compression release member and also comprises throttle-choke lever 12 means for actuating a throttle-choke lever means of the engine, and means for operatively interconnecting said actuating means and said throttle-choke lever means.

9. In' a four-stroke cycle internal combustion engine I having a cylinder block with a cylinder and with fuel intake passage means leading to said cylinder and with exhaust gas outlet passage means leading from said cylinder to the atmosphere: inlet valve means for opening and closing said fuel intake passage means with regard to said cylinder, reciprocable outlet valve means for opening and closing said exhaust gas outlet passage means with regard to said cylinder, each of said inlet and outlet valve means having stem means, rotatable cam shaft means with cams for actuating said valve stem means, a plurality of spring means respectively operatively connected to said inlet and outlet valve means and cont-inuously urging the same to close the passage means controlled thereby with regard to said cylinder, and annular compression release means surrounding the valve stem means of one of said valve means and movable independently of said cam shaft means in axial direction of said last mentioned valve stem means and relative thereto for moving said one valve means against the thrust of said spring means into position for opening the passage means controlled thereby with regard to said cylinder, said annular compression release means comprising two cam members respectively having oppositely located cam surfaces and bail means interposed between said cam surfaces.

References Cited by the Examiner UNITED STATES PATENTS 607,566 7/1898 Jacobson 123- 182 854,035 5/1907 Hansen-Ellehammer 123-182 1,161,417 11/1915 Schwerdtfeger 123182 1,482,650 2/1924 Hebb 123182 1,525,956 2/1925 Sargent 123--75 2,433,447 12/1947 Furtossetal 123-182 FOREIGN PATENTS 564, 30 11/1932 Germany.

MARK NEWMAN, Primary Examiner.

RICHARD B. WILKINSON, Examiner.

L. M. GOODRIDGE, Assistant Examiner. 

1. IN A FOUR-STROKE CYCLE INTERNAL COMBUSTON ENGINE HAVING A CYLINDER BLOCK WITH A CYLINDER AND WITH FUEL INTAKE PASSAGE MEANS LEADING TO SAID CYLINDER AND WITH EXHASUT GAS OUTLET PASSAGE MEANS LEADING FROM SAID CYLINDER TO THE ATMOSPHERE: INLET VALVE MEANS FOR OPENING AND CLOSING SAID FUEL INTAKE PASSAGE MEANS WITH REGARD TO SAID CYLINDER, RECIPROCABLE OUTLET VALVE MEANS FOR OPENING AND CLOSING SAID EXHAUST GAS OUTLET PASSAGE MEANS WITH REGARD TO SAID CYLINDER, EACH OF SAID INLET AND OUTLET VALVE MEANS HAVING A VALVE STEM AND PUSH ROD MEANS OPERABLE TO ACT UPON THE RESPECTIVE VALVE STEM PERTAINING THERETO FOR OPENING THE RESPECTIVE VALVE MEANS, ROTATABLE CAM SHAFT MEANS WITH CAMS FOR ACTUATING SAID PUSH ROD MEANS, A PLURALITY OF SPRING MEANS RESPECTIVELY OPERATIVELY CONNECTED TO SAID INLET AND OUTLET VALVE MEANS AND CONTINUOUSLY URGING THE SAME TO CLOSE THE PASSAGE MEANS CONTROLLED THEREBY WITH REGARD TO SAID CYLINDER, AND A MECHANICALLY TURNABLE ANNULAR COMPRESSION RELEASE MEMBER SUBSTANTIALLY COAXIALLY ARRANGED WITH REGARD TO THE STEM OF ONE OF SAID VALVE MEANS AND TURNABLE RELATIVE THERETO WHILE SURROUNDING THE PUSH ROD MEANS PERTAINING TO SAID LAST MENTIONED STEM, SAID COMPRESSION RELEASE MEMBER BEING OPERABLE IN RESPONSE TO A TURNING MOVEMENT THEREOF IN ONE DIRECTION TO CARRY OUT A MOVEMENT IN AXIAL DIRECTION OF THE STEM OF SAID ONE VALVE MEANS AND IN THE OPENING DIRECTION THEREOF TO ACTUATE THE VALVE STEM OF SAID ONE VALVE MEANS SO AS THE LATTER OPENS THE PASSAGE MEANS CONTROLLED THEREBY WITH REGARD TO SAID CYLINDER, SAID COMPRESSION RELEASE MEMBER BEING OPERABLE INDEPENDENTLY OF EACH OF SAID PUSH ROD MEANS SO AS SELECTIVELY TO BE HELD STATIONARY RELATIVE THERETO. 